Powertrain control in a motor vehicle generally involves reading driver and vehicle inputs, such as accelerator pedal position, vehicle sensor data, torque requests, and communicating these inputs to an Engine Control Module (ECM) and a Transmission Control Module (TCM). The ECM calculates a desired axle torque from the driver and vehicle inputs. The desired axle torque is then communicated to the engine and to the TCM. The engine is controlled based on the desired axle torque to produce an actual axle torque. Meanwhile, the TCM calculates a desired speed or gear ratio from the desired axle torque and the vehicle speed. The desired gear ratio is then communicated to the transmission. The transmission is controlled based on the desired gear ratio to produce an actual gear ratio. The actual axle torque and the actual gear ratio define the operating conditions of the motor vehicle.
While this system of powertrain control is useful for its intended purpose, there is room in the art for improvements in powertrain control that provide dynamic control of the axle torque to balance performance and fuel economy, especially in powertrains having a continuously variable transmission or stepped transmissions with multiple gears.